Chair base



FIG. 1 is a perspective view of a chair base, showing my new design;

FIG. 2 is a top plan view;

FIG. 3 is a bottom plan view;

FIG. 4 is a side elevational view;

FIG. 5 is an alternate side elevational view;

FIG. 6 is an elevational view, showing the side not shown in FIG. 4;

FIG. 7 is a perspective view of a chair base, showing an alternate embodiment of my new design;

FIG. 8 is a top plan view of the alternate embodiment;

FIG. 9 is a bottom plan view of the alternate embodiment; and

FIG. 10 is a side elevational view of the alternate embodiment, showing one of four identical sides. 

The ornamental design for a chair base, as shown and described. 